Hello,

i bought a this 3 way switch for staircase with light at the bottom and top of the staircase. 
May the top box I have 3 sources of wire bundle:

main power identified on top right of the picture (black hot, and white)

top left bundle of three wires (red black and white) switch contrôler? 
on bottom left 2 wire bundle black and white. I imagine connect to the light fixture.

at the bottom side of the staircase 2 bundle wires 

one connected to switch (black white and red)

other bundle not connected to anything.

i have tried everything and can't figure out what to to. 
the smart switch will always flash red (wires incorrectly connected)

attached pictures from both wall boxes. Ignore the stickers (I have added them)